Altitude sickness usually resolves by itself within six to 48 hours. The main treatment involves going down to a lower altitude (descent) as quickly and safely as possible. The symptoms of moderate altitude sickness generally improve within 24 hours on reaching an elevation that is at least 1,000 to 2,000 feet lower. All the symptoms should subside completely within three days.
What does altitude sickness do to your body?
AMS happens if the body is not able to adjust to the low air pressure and low oxygen at high altitudes. The low oxygen (hypoxia) levels in the air and blood cause the blood vessels of the brain to swell (dilate). The dilated blood vessels in the brain may cause headaches and swelling of the brain. The swelling puts pressure on the brain, squeezing it against the skull.
Altitude sickness may rarely advance to a more severe form of the illness called high altitude cerebral edema (HACE). HACE occurs when brain swelling becomes severe manifesting as headache, confusion, lethargy, lack of coordination, irritability, vomiting, seizures, coma and eventually death if untreated.
Severe altitude sickness may cause the tiny blood vessels (capillaries) in the lungs to become swollen and leaky. This leads to an accumulation of fluid in the air sacs of the lungs. This condition is known as high altitude pulmonary edema or HAPE. HAPE severely decreases the exchange of oxygen in the lungs which may cause breathing difficulties and even death. If left untreated it may progress to severe breathlessness even at rest, a persistent cough sometimes with blood, chest tightness and severe weakness. Ultimately, it advances to confusion, unconsciousness and death.